Artemisinins in the Clinical and Veterinary Management of Kinetoplastid Infextions

ABSTRACT

The invention relates to the treatment of kintoplastid infections by administering a pharmaceutical composition containing an extract from the plant  Artemisia annua . The invention also relates to isolated, semi-synthetic and synthetic artemisinins that show improved efficacy in treating kinetoplastid infections. This invention also relates to a method of treating kintoplastid infections with artelinic acid and artemisinins and where Artelinic acid is administered orally.

GOVERNMENT INTEREST

The invention described herein may be manufactured, used and licensed byor for the U.S. Government.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to methods of treating and managing kinetoplastidinfections by administering artemisimins and artelinic acid.

2. Brief Description of Related Art

Trypanosomiasis is a re-emerging [1-3] tropical infectious disease thatposes a real challenge to public health countermeasures. According tothe World Health Organization (WHO) [4], about 36 sub-Saharan countriesin West, Central, and East Africa and some 22 Latin countries in Centraland South America delimit its geographic prevalence zone, thus, leadingto the establishment of two distinct manifestations of the disease:African trypanosomiasis and American trypanosomiasis.

Trypanosoma species pathogenic to human beings and domestic animals inAfrica, cause one of the world's most neglected tropicalinfections—African trypanosomiasis [3]. Nearly eliminated in the 1960s,African trypanosomiasis has been making an alarming comeback due tocivil wars, population displacements, and the collapse of public healthsystems mainly due to political instability(www.accessmed-msf.org/documents/ssfactsheet.pdf) [1]. Human Africantrypanosomiasis (HAT) threatens 60 million [1,3-6] men, women, andchildren among, principally, the rural populations, but actually eventhe citadin populations, in countries of high endemicity such as Angola,southern Sudan, the Democratic Republic of Congo, and northern Uganda.The incidence rate in HAT is estimated between 300,000-500,000 casesannually[3-6] and only 3 to 4 million people at risk are under regularmedical surveillance (http://www.who.int/inffs/en/fact259.htlm). Inanimal African trypanosomiasis (AAT), the infection threatens about 50million head of cattle with an estimation of 3 million deaths per yearin livestock(http://www.fao.org/ag/againfo/programmes/en/paat/disease.htlm).

American trypanosomiasis (“Chagas disease”) occurs mainly in countriessuch as Brazil, Chile, Mexico, Uruguay, Paraguay, Bolivia, and Argentina[10,11]. Over 13 million persons in the Southern American region are atrisk of infection and the annual incidence rates of the disease reaches200,000 cases in 15 endemic countries [10]. The bloodstream protozoanTrypanosoma cruzi [10-12] is the etiologic agent of Chagas disease.

Host-to-host transmission is mediated by blood-sucking triatomine bugssuch as Triatoma infestans [11]. Moreover, blood transfusion andcongenital transmission have been encountered, particularly, in humans[10]. These pathogens are all cyclically transmitted to mammalian hoststhrough the bite of haematophagus tsetse flies (Glossina morsitans,Glossina palpalis) [9] serving as vectors of the disease.

The consistent decimation of human populations and cattle by Africantrypanosomiasis has reached dramatic proportions and represents a socialand economical obstacle for development [6,7]. In AAT, breeding animallosses are estimated to cost African farmers US$4.5 billion per year[8]. Bloodstream flagellated protozoan, members of the taxonomic genusTrypanosoma, are incriminated as the causative agents [1-7]. Trypanosomabrucei rhodesiense and Trypanosoma brucei gambiense provoke humanAfrican trypanosomiasis (“sleeping sickness”) while Trypanosomacongolense, Trypanosoma simiae, Trypanosoma vivax and Trypanosoma bruceibrucei cause animal African trypanosomiasis (“nagana”)[http://www.vetuga.edu/vpp/gray_book/FAD/AAT.htm].

In the particular case of human African trypanosomiasis, thetrypanosomes multiply in the blood and lymph glands of the infectedpersons, therefore, defining the first-stage of sleeping sickness[5,13]. The symptoms in this early stage are characterized by bouts offever, headaches, skin itching, pain in the joints, gradual loss ofweight, nausea and vomiting [6,9]. Later, in the second stage, thetrypanosomes cross the blood-brain barrier and invade the centralnervous system to cause sleeping sickness. Sleeping sickness ischaracterized by neurological disorders such as mental confusion,sensory disturbances and poor muscular coordination, and reversal of thecircadian sleep/wake cycle (insomnia in the night, drowsiness in thedaytime) [5,9,13,14] hence, the nickname “sleeping sickness”. In theabsence of effective treatment, sleeping sickness invariably leads todeath [3,6].

Control measures for African trypanosomiasis are directed either againstthe transmission vector through eradication of the tsetse fly, oragainst the causative pathogen, trypanosomes. Although vector controlstrategies had been effective in the past, they have been virtuallyabandoned because of their harmful effects on the environment [7].Treatment of infected persons with the few available synthetictrypanocidal agents have shown significant drawbacks [15-17] related tohigh cost, host toxicity, limited oral bioavailability, and arequirement for hospitalization during the entire course of treatment.The emergence of drug resistance has also limited the choice andeffectiveness of affordable agents in clinical use. Moreover, the typeof treatment depends on the stage of the disease: hemolymphatic (firststage) or cerebral (second stage). Effectiveness in the second stagerelies on the ability of the drug to cross the blood-brain barrier andreach concentrations high enough to kill the infective trypanosome. Thefour trypanocidal drugs, shown below [5,6,13] that have been clinicallyused up-to-date against sleeping sickness are, in chronological order—:Suramin (developed in 1921 against T. b. rhodesiense in the first-stageinfection), Pentamidine (discovered in 1941 against first-stage T. b.gambiense infection), Melarsoprol (developed in 1949 against bothhuman-infective Trypanosoma subspecies in cerebral infection), andDifluoromethyl ornithine (developed in 1981 as an alternative toMelarsoprol treatment failure in cerebral sleeping sickness). FIGS. 1 aand b show the known trypanocidal drugs for early stage infection whichare suramin and pentamidine, respectively. Suramin has no oralbioavailability and causes hemolysis and kidney disease. Pentamidine hasno oral bioavailability, is an immunosuppressive and causes bleeding.FIGS. 1c and 1d show the known trypanocidal drugs for cerebral infectionwhich are melarsoprol and difluoromethyl ornithine (DFMO), respectively.Melarsoprol has no oral bioavailability and causes tumors in the brain,blood in the urine and stomach pain. DFMO has no oral bioavailabilityand has a high susceptibility to resistance.

In the absence of prospective vaccine candidates for the disease, thelimitations and drawbacks of these drugs emphasize the crucial need todevelop new safe, effective and affordable drugs (trypanocides) againstall forms of human and veterinary trypanosomiasis.

The Chinese plant Artemesia annua has been used to treat malaria forcenturies. Research in the past three decades have uncovered artemisininderivatives like artemisinin, dihydroartemisinin, artemether, artesunatethat have played a critical role in the management of infectios causedby the multi-drug resistant malaria parasite, Plasmodium falciparum.Artemisinin has also been reported to be selectively active againstcancer cells in vitro [39]. Utzinger et al. have demonstrated the use ofartemisinin derivatives against tropical parasite species Schistosoma,responsible for schistosomiasis [40]. The effect of artemisinin and itsderivatives on Leishmania major, another tropical parasite provokingleishmaniasis has also been reported [41].However, the widespread use ofthis class of semi-synthetic artemisinin derivatives have been limitedby the high cost of production, low bioavailability and long treatmentregimens.

African, Asian and Amerindian societies have a rich tradition [17] inthe use of plants for medical care. However, only few reports exist onthe phytochemical treatment of sleeping sickness [17] and otherkinetoplastid infections. Artemisinins have never before been used totreat human and veterinary trypanosomiasis. Until now, no experimentalstudy has been carried out to establish the effectiveness of artemisininor its derivatives on any Trypanosoma species.

The inventors are the first report on the trypanocidal potency ofartemisinin and by extension, artemisinin-derived compounds, includingartelinic acid.

Therefore, an object of the invention is to prepare a pharmaceuticalcomposition containing artemisinin lead compounds from natural resourcesfor the treatment of trypanosomiasis. Medicinal plants such as Artemesiaannua have secondary metabolites of diverse molecular structures,physico-chemical properties, and pharmacological activities and offer aninvaluable reservoir for new remedies.

Another object of the invention is to provide a cost effective treatmentfor kinetoplastid infections.

Another object of the present invention is to provide a method oftreating humans and other mammals with kinetoplastid infections withartemisimin compounds such as artemisinin and artelinic acid.

Other objects, features and advantages of the present invention willbecome apparent from the following detailed description. It should beunderstood, however, that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

SUMMARY OF THE INVENTION

The invention relates to the treatment of kintoplastid infections byadministering a pharmaceutical composition containing an extract fromthe plant Artemisia annua. The invention also relates to syntheticartemisinins that show improved efficacy in treating kinetoplastidinfections. This invention also relates to a method of treatingkintoplastid infections with artelinic acid and artemisinins.

The accompanying drawings show illustrative embodiments of the inventionfrom which these and other of the objectives, novel features andadvantages will be readily apparent.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1a is the chemical structure for suramin;

FIG. 1b is the chemical structure for pentamidine;

FIG. 1c is the chemical structure for melarsoprol;

FIG. 1d is the chemical structure for difluoromethyl ornithine (DFMO;

FIG. 2 is a Flow diagram showing the bioassay-guided isolation of activeconstituents of plant C-1 leading to C-46;

FIG. 3 is a flow diagram showing the bioassay-guided isolation of activeconstituents of plant C-1 leading to C-53;

FIG. 4 a is the chemical structure of artemisinin C-46;

FIG. 4 b is the chemical structure of Artelinic acid;

FIG. 5 a is a photograph showing untreated Leishmania mjor amastigotes;

FIG. 5 b is a photograph showing the effect of 1 μg/ml MeOH extract ofArtemisia annua on Leishmania major amastigotes;

FIG. 5 c is a photograph showing the effect of 10 μg/ml MeOH extract ofArtemisia annua on Leishmania major amastigotes;

FIG. 5 d is a photograph showing the effect of 100 μg/ml MeOH extract ofArtemisia annua on Leishmania major amastigotes;

FIG. 6 is a photograph showing the foot of an untreated mouse; and

FIG. 7 is a photograph showing a mouse foot with the effect of 100 μg/mlMeOH extract treatment for 14 days.

DETAILED DESCRIPTION

The present invention relates to treatment of kinetoplasmid infectionssuch as Leishmaniasis and Trypanosomaisis with artemisinins such asartelinic acid and/or trioxolane compounds.

The antimalarial activity of the artemisinins is believed to reside inthe generation of toxic free oxygen radicals subsequent to theinteraction with heme released from the metabolism of hemoglobin. Theinventors have found that artemisinins and synthetic artemisinins, inparticular, artelinic acid and trioxolane compounds, are effective in amethod of treatment of kinetoplasmid infections, particularly againstLeishmania and Trypanosoma.

The structural identity, and biological activity of compounds extractedfrom the medicinal plant Artemesia annua “Plant C-1” was established.For these experiments, chromatographic techniques were used for totalpurification of the active principles. Various spectroscopic methods andconventional database analysis were also utilized for chemical structureelucidation. The identified candidates were subjected to standardbioassay protocols for in vitro characterization of their trypanocidalactivity and also selective toxicity against trypanosomes versusmammalian host cells.

The extract of the plant Artemesia annua was shown to kill Leishmaniaparasited cultivated within mouse macrophages in vitro in adose-dependant manner without significant toxicity to the mousemacrophages. The results were duplictated using commercially sourcedartemisinin. The active compound in the compound was isolated andpurified and chemically identified as artemisinin.

Materials and Methods

a. Plant Material

Artemesia annua can be obtained in countries where it is cultivated suchas its native China and Kenya. Freshly cut leaves of Artemesia annuawere collected in Kenya, sun-dried and then ground into powder that canbe stored in a refrigerator prior to extraction.

In the case of artemisinin, the compound was extracted from Artemisiaannua with 70% aqueous EtOH at room temperature for 48 h (firstextraction) and then 24 h each for the second and third extraction. Theextracts were combined and concentrated under reduced pressure to obtainthe EtOH extract. The EtOH extracts were purified by organic solventfractionation and a combination of chromatographic procedures such asion exchange on a DIAION HP-20 column and hydrophobic interaction on anODS column and gel filtration on a Sephadex column. The active fractionswere then identified. The following experiment confirms that thecompounds that were extracted are efficacious against kinetoplastidinfection and are artemisinins.

b. General Experimental Procedures: (Plant C-1)

¹H-NMR (500 MHz) spectra were measured on JEOL Lambda 500 spectrometerin CHCl₃-d₁ as well as MeOH-d₄ with TMS as an internal standard. ¹³C-NMR(600 MHz) and 2D-NMR (600 MHz) data were recorded on Varian Inova 600 inCHCl₃-d₁. Fast-atom bombardment (FAB) and high-resolution fast-atombombardment (HR-FAB) mass spectra were recorded in positive ion mode JMSSX-102 spectrometer. For column chromatography, silica gel (Fuji SylisiaBW-200, Merck), ODS (Cosmosil 75C₁₈ OPN, Nacalai) were used. Thin-layerchromatography (TLC) analyses were performed over normal phasepre-coated plates (Kiesel gel 60F₂₅₄, Merck) and reversed-phasehigh-performance thin-layer chromatography (HPTLC) plates (RP-18WF_(254S), Merck). Spots on chromatograms were detected under UV light(254 and 365 nm) and by spraying with phosphomolybdic acid (5g, EtOH 100mL), vaniline/H₂SO₄ (vaniline 5g, conc. H₂SO₄ 95 mL), andp-anisaldehyde/H₂SO₄ (AcOH 5 mL, conc. H₂SO₄ 25 mL, EtOH 425 mL,p-anisaldehyde 25 mL) followed by heating. For high-performance liquidchromatography (HPLC), detection of analytes was carried out with arefractive index detector (Shodex RI-71). For in vitro trypanocidalassay, stock solutions of samples were prepared in DMSO (Wako, forbiochemical assay) which concentration in culture medium never exceeded1%. Pentamidine (Sigma) was used as a positive control. For cytotoxicevaluation in vitro, mitomycin C was used as the positive control.

c. Trypanosome Stocks

Culture suspension of Trypanosoma brucei brucei (T. b. brucei) wasobtained from Research Institute for Microbial Diseases (OsakaUniversity, Japan). Trypanosomes were subcultured in appropriate medium(see 5.1.2) as frequently as needed to avoid overgrowth, and maintainedin culture flasks at 37° C. in a humidified, 5% CO₂ atmosphereincubator. In addition, parasite culture stabilates were prepared bysuspending trypanosomes centrifugation (1500 rpm, room temperature, 3min) pellet in 1 mL of a mixture of 77% (v/v) trypanosome dilutionbuffer [56] and 33% (v/v) glycerol. The whole volume was transferredinto cryotubes and stored at −80° C. until further needed.

d. Culture Medium for Trypanosoma brucei brucei

The axenic cultivation of the bloodstream forms of T. b. brucei wasperformed in Iscove's Modified Dulbecco's Medium (Gibco) supplementedwith L-glutamine and 25 mM HEPES buffer. Additionally, 15%heat-inactivated (56° C., 40 min) fetal bovine serum (FBS, MultiSer) andalso 0.05 mM bathocuproine disulfonic acid disodium salt (Dojin), 1.5 mML-cystein (Nacalai), 1.0 mM hypoxanthine (Nacalai), 0.16 mM thymidine(TCI), 0.2 mM 2-mercaptoethanol (Sigma), and 1.0 mM sodium pyruvate(Nacalai) were aseptically incorporated in the culture medium.

e. Trypanocidal Assay

All fractions obtained stepwise in the course of the separation processof the plant crude extracts were assessed for their in vitro activityagainst T. b. brucei. Various concentrations of test samples wereprepared in neat dimethyl sulfoxide (DMSO, Wako-for biochemical assay)then diluted in the culture medium so that DMSO content decreased to 10%in the medium. Trypanosomes were harvested at late exponential growthlevel, counted with a hemocytometer (Erma Tokyo 7059), and resuspendedby appropriate dilution in culture medium for achieving a final densityof 1×10⁴ cells/mL. Aliquots of 90 μL of T. b. brucei suspension (1×10⁴cells/mL) were transferred in wells of a Becton Dickinson 96-wellmicroculture plate. Then, 10 μL of each sample preparation containing10% DMSO were added to each inoculum well, achieving a finalconcentration of 1% DMSO. The microculture plate was incubated in ahumidified, 5% CO₂ atmosphere incubator at 37° C. After successively 24,48, and 72 hr-incubations, parasites viability was determined byobserving directly inside the wells of the microculture plate with anoptical microscope (Injectoscope model IMT-YF/Olympus). The in vitrotrypanocidal potency of each sample was then evaluated and translatedinto mathematic symbols [(−): <80% growth inhibition level, (±): ≧80%growth inhibition level, (+): 100% growth inhibition level]. Controlwells with the commercial drug pentamidine (positive control) and thesolvent DMSO only (negative control) were also achieved in the sameconditions as the test samples. A blank (parasites only in culturemedium) was also included for reference.

f. Culture Medium for HeLa S3 Cells

An axenic culture of human carcinoma HeLa S3 cell line was establishedin Dulbecco's Modified Eagle's Medium (D-MEM, Sigma) supplemented with4500 mg glucose/L, L-glutamine, NaHCO₃, and pyridoxine HCl, to which 10%heat-inactivated (56° C., 40 min) fetal bovine serum (FBS, MultiSer) wasadded.

g. Sample Preparation for Cytotoxic Evaluation in vitro

Plant chromatographic fractions, which have shown potent trypanocidalactivity in vitro, were selected for cytotoxicity assay. Previouslydissolved in neat DMSO (Wako-for biochemical assay), an aliquot of 10 μLof each test sample was diluted in 490 μL of the cell culture mediumwiththe intent of decreasing the DMSO concentration to 2% in the medium.

h. Cytotoxicity Assay in vitro

HeLa S3 cells maintained in culture dish (Sumilon) were washed withDulbecco's phosphate saline buffer (−) [DPBS (−), Nissui PharmaceuticalCo., Ltd] after syphonating the culture medium. Adherent cells werereleased from their dish bottom substrate by adding trypsin (Nacalai)and gently tapping with hand on the round lateral side of the dish.Thus, trypsinized cells were harvested, suspended in culture medium thencentrifuged at 800˜1000 rpm for 3 min at room temperature. Afterremoving the supernatant, the remaining pellet was resuspended in theculture medium. Cells were counted with a hemocytometer (Erma Tokyo7059), and then diluted appropriately to achieve a final density of1×10⁵ cells/mL in the culture medium. Later on, cells were seeded in a96-well microtiter plate (Becton Dickinson), each well containing 100 μL(1p33 10 ⁵ cells/mL) of cell suspension. Then, 100 μL of test samplespreparation (see 5.2.2) were added in triplicate for each concentrationinto respective wells, thus achieving a final concentration of 1% DMSO.Respective triplicate wells for the positive control (mitomycin C) andthe negative control (1% DMSO only in culture medium) were alsoincluded. After 72 hr-incubation at 37° C. in a humidified, 5% CO₂atmosphere incubator (Sanyo), 25 μL of MTT[3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium bromide] [57-59]reagent were added to each well including controls. The microtiter platewas returned in the same incubator for an additional 3 hr-exposure at37° C. to allow the formazan [57-59] crystals to accumulate. Then,supernatants were syphonated from the wells and 200 μL of DMSO wereadded to solubilize the formazan crystals. After shaking (MS1 MinishakerIKA) for 3-5 min, the absorbance in each well was measured at 540 nm ina microtiter plate reader (ImmunoMini NJ-2300). The percentage ofcytotoxicity (growth inhibition level) was calculated as (A-B)/A×100,where A is the mean optical density of negative control wells and B isthe mean optical density of test sample wells.

i. Bioassay-Guided Isolation of Active Constituents of Artemisinin

Dried and pulverized powder from “plant C-1” (2.3 kg) were extractedthree times with 80% ethanol after 24-hr maceration (first time) and3-hr maceration (second and third time) at room temperature. The liquidextracts were combined, filtered, and concentrated under reducedpressure with a rotary evaporator below 30° C. The ethanolic residue(240 g) obtained exhibited a complete inhibition of trypanosomes growthat 30 μg/mL after 24-hr exposure and 100% growth inhibition in vitroagainst T. b. brucei at 100 μg/mL after 24-hr exposure. This residue waslater on dissolved in double-distilled water, then subjected tosolvent-solvent partition in EtOAc and n-BuOH to yield, after solventevaporation, 72 g of EtOAc extract, 74 g of n-BuOH extract, and 94 g ofH₂O extract. The strongest trypanocidal activity in vitro was observedin the EtOAc extract exhibiting 100% and ≧80% growth inhibition againstT. b. brucei, respectively, at the concentrations of 50 μg/mL and 5μg/mL after 24 hr-exposure. This most potent EtOAc residue was appliedto SiO₂ gel column and eluted successively with binary solvent mixturesof hexane: EtOAc=4:1→1:1→1:1.5→1:2→100% MeOH. The eluted fractions weremonitored by normal phase TLC and similar fractions were pooled intofive main fractions named A (280 mg), B (341 mg), C (1.72 g), D (1.84g), and E (690 mg). Among them, fraction C was the only one that showedtrypanocidal activity until the low concentration value of 1 μg/mL, thusfeaturing ≧80% growth inhibition after 24-hr incubation. Furtherseparation of fraction C carried out by reversed-phase ODS columnchromatography and eluting gradually with 60% MeOH→80% MeOH→90%MeOH→100% MeOH yielded seven fractions named from C-1 to C-7. FractionsC-4 (629 mg), C-5 (16 mg), and C-6 (139 mg) showed the highestbiological potency and an encouraging selectivity toward HeLa cell invitro at 0.5 μg/mL with, respectively, 100% trypanocidal level and 5.5%cytotoxic level for C-4, ≧80% trypanocidal level and 10.5% cytotoxiclevel for C-5, and ≧80% trypanocidal level and 14.9% cytotoxic level forC-6.

Firstly, C-4 was subjected to final purification with HPLC (column: 5SL-II type Waters, 10×250 mm i.d.; flow rate: 3.0 mL/min; detection:refractive index detector at range 512; eluent: hexane/EtOAC=8/1)leading to isolation of C-46 (7.1 mg) at a t_(R) of 21.27 min (FIG. 2),whose trypanocidal activity in vitro was ≧80% growth inhibition after24-hr incubation and the cytotoxic level in vitro was 17.3% at 1 μg/mL.Secondly, C-5 was purified by normal phase HPLC (column: 5 SL-II typeWaters, 10×250 mm i.d.; flow rate: 3.0 mL/min; detection: refractiveindex detector at range 512; eluent: hexane/EtOAC=7/1) affording C-53(1.1 mg) at t_(R)=12.99 min (FIG. 3). Because of the small amountyielded by C-53, extensive spectral data measurement was inconvenient.Only ¹H-NMR data could be obtained. Thus, purification was repeatedstarting off with a larger quantity of EtOAc extract. Fortunately, 11.0mg of C-53 were obtained. According to the bioassay outcome, C-53 showed≧80% growth inhibition in vitro against T. b. brucei after 24-hrincubation at 1 μg/mL, and only 3.1% inhibition ratio against HeLa cellsin vitro at 5 μg/mL.

j. Chemical Structure of C-46

Comparison of ¹H- and ¹³C-NMR, ¹H-¹H COSY, HMBC, FAB-MS, and specificrotation data in our hands with those reported in the literature [34,35]led to conclusion that C-46 was (+)-artemisinin (FIG. 4).

¹H-NMR spectrum analysis for structure elucidation of C-46 indicated thepresence of doublet peaks, respectively, at δ1.19 (3H, d, J=7.4 Hz) andδ0.98 (3H, d, J=6.0 Hz), and a singlet peak at δ1.43 (3H, s). This setof peaks was indicative of the three methyl groups at C-13, C-14, andC-15, respectively. The signal observed at δ5.84 was assignable to H-5,which corresponding carbon signal was displayed at δ93.9 on the ¹³C-NMRspectrum. The signal that appeared at δ172.2 was assignable to thecarbonyl moiety of the lactone group at C-12. The signal that appearedat δ105.6 was due to the quartenary carbon C-4 activated by two geminaloxygen atoms. The peak observed at δ79.7 was due to the quartenarycarbon C-6 connected to an oxygen atom. In addition, the positive ionmode FAB-MS displayed [M+Li]⁺ at m/z 289 (65%), [M+Na]⁺ at m/z 305(100%), and [M+H]⁺ at m/z 283 (12%). Additionally, the optical rotationparameter revealed [α]_(D) ^(24pb =+41.5) (c=0.2, CHCl₃). Comparisonbetween spectral data in our hands with those in the literature databaseled to conclusion that C-46 corresponded to (+)-artemisinin (C₁₅H₂₂O₅,Mw=282).

k. Chemical Structure of C-53

Relevant ¹H- and ¹³C-NMR, ¹H-¹H COSY, HMQC, HMBC, NOESY, FAB-MS, andHRFAB-MS data were recorded; the specific rotation value was calculated.

C-53 has trypanocidal potency in vitro but is slightly weaker than thatof (+)-artemisinin. Nevertheless, from its chemical characterization,1D- and 2D-NMR, FAB- and HRFAB-MS, and specific rotation data that havebeen collected, spectral data analysis reveals that C-53 might bepolyalicyclic; containing three characteristic methyl substituents andan unsaturated lactone ring; displaying a molecular weight of 234associated to the chemical formula C₁₅H₂₂O₂. Accordingly, C-53 ispresumed to be a sesquiterpene lactone congenere of artemisinin, butobviously lacking the endoperoxide bridge. This activity is of moregeneral interest because the mechanism of action of artemisinins, as ananti-plasmodial or anti-tumoricidal agent, is believed by some to berelated to the presence of the endoperoxide bridge.

The information obtained by careful examination of C-53 and C46 as wellas other eluted compounds in the above experiment verify thatartemisinins are active ingredients in artemeseia anima that hinder thegrowth of kintoplastid infections. Both compounds Artemisinin andArtelinic acid belong to the same class of compounds and both have beenfound by the inventors in testing to be effective against leishmaniasisand other kinteplastid infections.

EXAMPLE 1

Preliminary drug screening (in vitro amastigote/macrophage culture) ofartemisinin and artelinic acid compounds.

Four compounds were obtained.

BN: 97471 artelinic acidZW: 60909 dihydroartemisinin

BN: BL 48816WR# 255131 (Beta-Arteether) BN: BL 50129 WR#: 249309(Artemisinin QHS)

The four compounds were dissolved in the respective solvents asindicated in the table below (Table 1) and were tested againstLeishmania major ATCC 50122 amastigotes in vitro in a mouse macrophagesystem. A positive (Pentostam) and negative (culture medium) controlswere set for each plate. Compounds were tested at 2.0 μM in a totalvolume of 2-0 mis. Drug was added to well every 4 hours×1, 2 and 3, andresults shown in (Table 2) below.

TABLE 1 Compound. Solvent. Conc. Used. Volume. 1 Artelinic acidMethanol. 2.0 μM  5.6 μl/2 ml. 3 Dihydro artemisinin DMSO. 2.0 μM 1.1μl/2 ml 5 B-Arteether DMSO 2.0 μM 1.18 μl/2 ml  6 Artemisinin Methanol.2.0 μM 1.2 μl/2 ml

Results

TABLE 2 Compound added Compound added Compound added Compound q4h × 1q4h × 2 q4h × 3 Artelinic Acid No intracellular No amastigote was same 1amastigote was seen in the seen in the macrophages. ctoplasm of theApart from staining macrophages. pinkish, the cells Cytoplasm stainedcytoplasm looked pinkish instead of mushy and seem to purplish which isdesentegrate. an indication of cell cytotoxicity. Dihydro About 50% ofAbout 30% of About 5-7% of artemisinin 3 macrophages had macrophages hadmacrophages had intracellular intracellular intracellular leishmanialeishmania leishmania amastigotes. Cells amastigotes. Cells amastigotes.About morphology was morphology was 30% of macrophages normal. normal.had intracellular leishmania amastigotes B Arteether About 90% of About90% of About 50% of macrophages had macrophages had macrophages hadleishmania leishmania leishmania amastigotes similar to amastigotessimilar to amastigotes similar to the Negative control the Negativecontrol the Negative control Cytoplasm stained Cytoplasm stainedCytoplasm stained poorly (pinkish). poorly (pinkish). poorly (pinkish)with mild cytotoxicity. 6 Artemisinin No difference same same betweencontrol and the macrophages subjected to the test compound. About 80% ofthe cell had between 4-7 parasites per macrophage. Cell morphology wasnormal.

The results of the initial screen showed that Artelinic acid at 2 uMcleared all of the amastigates in macrophages. Observer also notedpinkish staining of the cytoplasm of the macrophages that wasinterpreted as cell toxicity. However, similar changes were also notedin the negative control that had no compound added. The effectiveness ofthe WRAIR compounds tested in the screen was judged to be:

Artelinic acid>>>Dihydroartemisinin>Beta Arteether>>Artemisinin.

Because of the high potency of Artelinic acid relative to the othercompounds, the experiments were repeated with different doses ofArtelinic acid alone. Additionally, the addition of drug to culturewells q4h did not seem to affect the results for this compound (Table2). Hence, Artelinic acid was added once in the dose responseexperiments (Table 3).

The initial observation implicating Artemisinins was obtained with crudeextracts from the plant (Artemesia annua. On the strength of theseresults Artemisinin-derived compounds that had been synthesizedpreviously as potential anti-malarials were secured from the WRAIRinventory and tested (See U.S. Pat. No. 4,791,135, incorporated in itsentirety by reference for the preparation of synthetic artemisinins,dihydroartemisinins, and artesunic acid.). The active principle in theplant extract was prepared into pharmaceutical compositions suitable fortreating kinetoplastid infections.

Pharmaceutical compositions containing the active ingredients from theplant artemesia annua, including artemisinins and artelinic acid can beprepared using any known pharmaceutical carrier suitable for i.p.injection including but not limited to saline. Carriers for oraladministration can be capsules or pills made by any known and acceptedpharmaceutical composition used for carrying active ingredients to thedigestive tract. Acceptable doses for oral administration are 4-8 ul/kgfor i.p or oral administration. Concentrations for in vitro testing are0.01 to 2.0 uM

Effects of Different Concentrations of Artelinic Acid (Dose Response) onLeishmania Amastigotes.

TABLE 3 Concentration. Observation Results. 2.0 μM All the leishmaniaamastigotes were cleared but the cell showed some marked pink staining.1.0 μM All the amastigotes were cleared from the macrophages and somevacuoles could be seen in the macrophage cytoplasm. Mild cell pinkstaining was noticed. 0.5 μM Cleared all the parasites in the cytoplasm.Some cells showed pinkish staining. 0.25 μM  Cleared all the Leishmaniaamastigotes and no noticeable pink staining of cells. The cellmorphology was normal as compared to the control cells. 0.1 μM There wasreduction of intracellular Leishmania amastigotes in the macrophages butunable to clear them completely. No pinkish stain of cells was noticed.0.05 μM  No effect of the drug was seen on either the Leishmaniaparasites or the macrophages. Control. 90% of the macrophages wereinfected with between 5-7 parasites per cell.

As shown in the results above (Table 3), killing of intracellularamastigotes was noted at concentrations as low as 0.1 μM of Artelinicacid and clearance was complete at doses as low as 0.25 μM of compound.

EXAMPLE 2 In vivo Testing in BALB/c Mice

Because of the marked potency of Artelinic acid in the clearance ofintracellular Leishmania amastigotes, an in vivo screen was undertakenusing BALB/C mice. One foot pad was infected with infective Leishmaniapromastigotes while the other foot served as control. After the infectedfoot pads had developed lesions, mice with similar size lesions wereselected and treated daily with test article for one week. The firstdoses were administered on 18 May. Lesions were measured with calipersprior to dosing and 9 days after commencement of treatment (27 May) andthe difference in lesion size calculated. The thickness of theuninfected footpad was also measured. Only Artelinic acid and the crudemethanol extract of the plant Artemesia annua, that had shown markedpotency in the mouse macrophage/amastigote in vitro screen were testedin vivo. Test articles were administered orally and intra-peritoneally(ip).

TABLE 4 Footpad Thick- ness (mm) Lesion Lesion Diff Unin- Size SizeLesion Com- Admin fected (mm) (mm) size pound Dose Route Foot Pre-RxPost-Rx (mm)* Artelinic 4 ul/Kg Oral 1.5 2.8 2.0 −0.8 acid Oral 1.5 2.72.0 −0.7 Oral 1.5 2.8 Ulcer- ated IP 1.5 2.6 2.1 −0.5 IP 1.5 2.5 2.2−0.3 IP 1.6 2.6 2.0 −0.6 Plant 8 ul/Kg Oral 1.2 2.9 2.0 −0.9 extractOral 1.3 2.8 2.0 −0.8 IP 1.4 2.7 2.2 −0.5 IP 1.5 2.8 1.8 −1.0 IP 1.5 2.62.7 +0.1 Pentostam 20 mg/Kg Oral 1.4 2.8 2.6 −0.2 Oral 1.5 2.7 2.9 −0.2Oral 1.5 2.7 2.9 +0.2 IP 1.6 2.8 2.3 −0.5 IP 1.5 2.8 3.0 +0.2 IP 1.6 2.62.7 +0.1 Control N/A 1.4 2.5 2.8 +0.3 *(positive value indicatesworsening and a negative value healing of the lesion with time)

Results (Table 4) show that Artelinic acid and plant extract ofArtemesia annua, containing artemisinins, either given orally or ip toBALB/c mice for one week led to a decrease in the size of Leishmaniamajor lesions induced in the footpad of the animals. Both Artelinic acidand plant extract were much more effective than Pentostam, the positivecontrol, at the doses and route of administration tested.

The in vivo experiments, are remarkable in that Artelinic acid and theactive ingredient in the plant extract, artemisinins, show potencyagainst Leishmania when administered orally. Moreover the in vitroexperiments demonstrate that these compounds do not require to bemetabolized into an active moiety by the liver for them to show potencyagainst intracellular Leishmania amastigotes.

The invention has been described herein with reference to certainpreferred embodiments. However, as obvious variations thereon willbecome apparent to those skilled in the art, the invention is not to beconsidered as limited thereto.

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1. A method of treating kinetoplastid infections comprising: (a)diagnosing a kinetoplastid infection in a mammal; and (b) administeringto said mammal a pharmaceutical composition wherein said compositioncontains a pharmaceutical dose of artemisinin or dihdro artemisininsufficient to decrease said kinetoplastid infection.
 2. (canceled) 3.(canceled)
 4. (canceled)
 5. The method of claim 1, wherein saidadministering is via an oral route or intraperitoneally.
 6. The methodof claim 1, wherein said dose is 4-8 ul/kg.
 7. The method of claim 1,wherein said kinetoplastid infections are selected from Leishmaniainfection and trypanosome infection.
 8. (canceled)
 9. A method ofinhibiting the growth of kinetoplastid organisms comprising:administering an effective amount of artemisinin or dihydro artemisininto said organisms.
 10. (canceled)
 11. A method of treating kinetoplastidinfections, comprising (a) diagnosing a kinetoplastic infection in amammal; (b) administering to said mammal a pharmaceutical dose ofartemisinin or, dihydro artemisinin.
 12. The method of claim 11, whereinsaid dose is 4-8 ul/Kg.
 13. The method of claim 11, wherein said mammalis a human.
 14. (canceled)
 15. (canceled)